Assuming no items, no previous damage, Multiscale, and Sandstorm, I assume it'd go like:
Garchomp used Outrage! It's super effective! (Multiscale activates, Dragonite loses about 2/3-3/4 its max HP) Dragonite used Dragon Dance! Attack rose! Speed rose! Dragonite is buffeted by the sandstorm Dragonite used Outrage! it's super effective! (80% of the time) Garchomp fainted! (80% of the time)
Dragonite can't Ice Punch. Specially-offensive Dragonite do have access to Ice Beam and Blizzard. YacheChomp could probably take an Ice Beam, and *might* survive a Blizzard, but I don't feel like doing the calcs.
Despite Garchomp being banned, I'm inclined to say Dragonite is still the better dragon due to its versatility. Garchomp only really does one thing, granted it does it a little too well. He either needs to lose 2 points in base speed or enough SpDef to stop surviving every ice attack under the sun with a Yache Berry.
Computers are a lot like air conditioners. Everything works fine, until you open up Windows. (437 laughs) MH Tri Hunter ID: 2EJVP8